Drop down list, limiting to corresponding values of other list selection

Hello all, longtime reader and first-time poster. I have a project for my work that I need to get done and I'm a bit stuck. I've attached the workbook that I'm using as well.

What I'm trying to do is populate the cells of a form, via drop-down selections, with data from another sheet within the workbook. The data set is "Sum Metal Model" sheet. In the "Form" sheet, columns A and B are very straighforward, and I have those ok; (although I would like to remove the duplicate entries for Profile), but it's column C (Color Group) that's causing me some issues. There can be multiple choices in column C for each Profile and Product, and I want the drop down to limit the choices specifically for that Product/Profile combination. I'm using 2007, and utilizing data validation with named ranges. I don't know if this needs to be coded, or if it's something that I'm clearly I.D. 10-T compliant about at the moment.

Appreciate any and all help.

-Swash